1. Field of the Invention
This invention is related to blur detection. More specifically, the present invention is related to a blurring motion detection device to detect blurring motions, such as from hand movements, on a camera and the like.
2. Description of the Related Art
Detection of blurring motion acting on a camera and compensation for image blur based on the detected blurring motion is well known in the industry. Methods well known in the industry are also used to increase the output accuracy of blur detection sensors as a type of drift countermeasure. An example of such methods includes Japanese Laid-Open Patent Publication number JP-A-4-211230, in which the average value of output values of the blurring motion detection sensors is calculated in a predetermined time. The average value is taken as a standard value (a blurring motion zero reference value) of the output of the blurring motion detection sensor.
However, the following problems existed in the aforementioned conventional technology.
When an average value is to be calculated from the output of a blurring motion detection sensor, the data to be collected to calculate the average value should preferable be free from irregular blurring motions acting on the camera. However, in photography of a stationary subject, photographic preparations may include changing the photographic field angle after framing is performed during manipulation of the composition of the photograph. Such movement of the camera may occur particularly in autofocus (AF) cameras after focusing is performed on the main subject to reframe the desired composition of the photograph where the main subject is no longer in the picture center. An output value of a blurring motion detection sensor during such movement of the camera will reflect an undesirably large offset or alteration movement. Accordingly, if the output value during such movement is used in calculating the average value, a standard value of high reliability cannot be obtained.
Moreover, if the data collected from the blur detection sensor for use in determining an average value becomes too old (i.e., data from a time in the past that is distant from the time of photography), then the data collected will not reflect conditions near the time photographic preparations end. Thus, when using such old data to calculate an average value, the true standard value at the time of photography cannot be obtained and a displacement occurs.
In addition, because the amount of movement during a panning motion is different from the amount of movement occurring at the commencement of the panning motion, a blurring motion zero reference value calculated from data collected during the panning motion commencement and panning motion execution is disadvantageous.